that you may be confusing concepts.
What you call "the Tombstone Story," the, so to say, crown jewel of which is the so-called gunfight at the O.K. Corral, is indeed mythic. That is, it has over time transcended the brute "facts" of the matter and become a metaphorical, iconic part of American folklore, as in truth has the whole mythology of the so-called Wild West, as has the myth of the so-called life and legend of Wyatt Earp. I seriously doubt that that is likely ever to change. Such myths, encrusted as they may be with historical inaccuracies, cannot be dispelled because they are, BY NOW, too deeply embedded in the historical zeitgeist and psychic culture of the country. They have, in sense--you of all people will appreciate the image--metastasized. They are immune to the chemotherapy that I suspect you would prescribe for them.
But I also suspect that that is not what you are asking about. I suspect that what you are asking about is not myths, but factual inaccuracies, which is something else entirely. And yes, needless to say, it is the job of the responsible historian to, not dis-spell, but correct them. It's called revision and is part and parcel of what historians do, typically as their research dredges new facts from the "record" that render the older ones replaceable and moot, and/or shine a brighter, sharper light on their possible meaning, and/or serve to bolster and buttress and augment those old ones, and/or fill-in certain pre-existing gaps in our knowledge.
There is a catch to this, however, which is called, hermeneutics, or the art of interpretation. It is called an art and not a science because there can exist a number of often conflicting interpretations about and conclusions to be drawn from the same set of facts depending upon who is doing the interpreting. Interpreting those facts is not a matter of 2+2 always and forever equals 4. It is not objective in that way. Even in the case of the most analytical, responsibly rigorous historical interpreter, there always will exist in such interpretations a degree of subjectivity (with respect to such matters as selection, sequencing, emphasis, angle or point of view, etc.), that is, the very subjectivity that accounts for differences of interpretation. Moreover, not every historical mind is as capable of plausible or persuasive interpretation as is every other mind. Historians have their own strengths and weaknesses.
Factual inaccuracies, where they exist, can and should be corrected, but for better or worse, those corrections in what I will call the "popular mind," are not likely to ever dis-spell the overarching mythic stature of the Tombstone Story, nor, even with those corrections solidly installed on the Record, are they likely to preclude conflicting and/or competing interpretations of them going forward. Which for my money is not necessarily a bad thing.
No definitive narrative, no consensus, no final word, open-endedness, the persistent asking of unanswered or previously unconsidered questions, ongoing controversy and conflict is part of what keeps interest in the subject, such as it is, somewhat alive. Certainly in that sense you are doing your responsible part, but if you expect to dislodge or even diminish the embedded status of the overall myth, if you have designs on "turning the tables" on that myth by debunking what is popularly perceived to be the heroes and replacing them with what is popularly perceived to be the villains, sorry, ain't gonna happen.
Historical accuracy to one side, such efforts are too little, too late. Besides, cruel truth, figuratively speaking, no one cares, unfortunately, not anymore.